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Failure Mode Effects Analysis (FMEA)
Presented By The University of Texas-School of Public Health This material was produced under grant number SH SH-1 from the Occupational Safety and Health Administration, U.S. Department of Labor. It does not necessarily reflect the views or policies of the U.S. Department of Labor, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.
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Learning Objectives By the end of this module participants should be able to: Identify the definition of Failure Mode And Effects Analysis (FMEA) Describe how to apply FMEA in the procedure of design, process, and project. Identify the terminology of failure mode, effect and cause, severity, occurrence, detection, and current controls. Select the appropriate methods and strategies to apply Failure Mode And Effects Analysis (FMEA) in the hospital nurse unit. Develop a completed FMEA using Risk Priority Numbers (RPNs) in the hospital nurse unit.
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The DMAIC Process with Tools
DAY 2 Define 3&4 Phase Tools: FMEA Quick Wins 5S The 8 Wastes Measure Analyze Improve Control
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What Is an FMEA? A structured approach to:
Identify the ways in which a product or process can fail Estimate the risk associated with specific causes Prioritize the actions that should be taken to reduce the risk A Process FMEA will: Capture the entire process and the key inputs (Xs) Identify ways the product or process can fail because of these Xs Facilitate the documentation of a plan to prevent those failures
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Applications For FMEA Design: Process: Project:
Used to analyze product designs before they are released to production. A DFMEA should always be completed well in advance of a prototype build. Focuses on product function. Process: Used to analyze manufacturing, assembly, or any other processes. Focuses on process inputs. This is the topic for this module. Project: Documents and addresses failures that could happen during a major program
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Key Source Material For An FMEA
PAPERWORK TURN STEAM ON TO DICY TANK LOAD DMF LOAD DICY LOAD 2MI 1 BILL OF MATERIALS ISO PROCEDURES REWORK SCALE ACCURACY PREHEATING LOAD ACCURACY CLEANLINESS RAW MATERIAL ENVIRONMENT (HUMIDITY) MIXER SPEED Process Map FMEA
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The FMEA Form The Analysis Section
Process Step/ Input Potential Failure Mode Potential Failure Effects S E V Potential Causes O C Current Controls Current Controls D E T R P N Action Section The FMEA Form The Analysis Section What is the Effect on the Outputs? How can this be found? If risk is too high, what can be done? What can go wrong with the Process Step? What are the Potential Causes? What is the Process Step How serious is such an Effect? How often is the cause likely to occur and result in a Failure Mode? How well can we detect a cause before it creates a Failure Mode and Effect? Estimated risk is “Sev” x “Occ” x “Det”
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Definition Of Terms – Failure Mode
Failure Mode: The way in which a specific process input fails If it is not detected and either corrected or removed, it may cause a negative “Effect” to occur Can be associated with a defect (in discrete manufacturing) or a process input variable that goes outside of specification Anything that an operator can see that’s wrong is considered a Failure Mode Note 1: Just because a dimension is out of spec (a Failure Mode), it does not imply with 100% certainty that the product will not function (an effect) Note 2: Just because the process is improperly setup (a failure cause), it does not imply with 100% certainty that the dimension will be out of spec (a Failure Mode)
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Definition Of Terms – Effect And Cause
Effect: The adverse impact on customer requirements. Generally has an external customer focus, but can also include downstream processes. A product or process that does not perform satisfactorily to design Cause: Whatever causes the Failure Mode to occur. How a specific part of the process (operation or component) can cause a Failure Mode. A worn spindle (cause) may cause a dimension to be out of tolerance (mode) which may cause the part to not fit (effect)
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Definition Of Terms – Severity, Occurrence, And Detection
Severity: An assessment of how serious the Failure Effect (due to the Failure Mode) is to the customer Occurrence: An assessment of the likelihood that a particular Cause will happen and result in the Failure Mode Detection: An assessment of the likelihood that the current controls will detect the Cause of the Failure Mode or the Failure Mode itself, should it occur, thus preventing the Failure Effect from reaching your customer. The customer in this case could be the next operation, subsequent operations, or the end user
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Definition Of Terms – Current Controls
Current Controls: Systematized methods/devices in place to prevent or detect failure Modes or Causes (before causing effects) Prevention-based controls may include Mistake Proofing, automated controls, setup verifications, Preventive Maintenance, and Control Charts Detection-based controls may include audits, checklists, inspection, laboratory testing, and Control Charts
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Rating Definitions Typical Scales
Severity Severity Occurrence Detection Hazardous without warning Very high and almost inevitable Cannot detect Loss of primary function High repeated failures Low chance of detection Loss of secondary function Moderate failures Moderate chance of detection Minor effect Occasional failures Good chance of detection No effect Failure unlikely Almost certain detection Occurrence Detection Rating High 10 Low 1 Note : Determine if your company has rating scales and rules In some companies, rating a “10” on severity may have legal consequences.
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Risk Priority Number (RPN)
A key output of an FMEA is the “Risk Priority Number” The RPN is a calculated number based on information you provide regarding: The likelihood of potential causes of Failure Modes The seriousness of the resulting effects The current ability of the process to detect the causes of the Failure Modes before they cause an effect to reach a customer It is calculated as the product of three (3) ratings, each one related to the severity, frequency, and detect ability RPN = Severity x Occurrence x Detection Regardless of RPN, high severity scores should be given special attention.
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Risk Priority Numbers (2)
The Risk Priority Number need not be limited to Severity, Occurrence, and Detection. Some examples: Add an “Impact” score to estimate the overall impact of the Failure Mode on the process (10 = high, 1 = low) Add an “EHS” rating to a project FMEA to incorporate possible environmental impact (10 = high, 1 = low) Add an “EOC” or Ease Of Completion (10 = easy, 1= hard) to help prioritize/focus projects
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Comments On Detection Scores
Low Det Score High Det Score Virtually certain Prevention Virtually no Prevention Failure Mode (Defect) Cause Effect High detection scores imply that we will not easily catch the existence of a Failure Cause until after the resulting Failure Mode creates a Failure Effect. Usually, this means that we detect the effect at the end of the line or, even worse, our customer finds it. A very low detection score generally implies that you catch the cause before it creates the Failure Mode.
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FMEA Model Cause Mode Effect Faculty inverter High particle count
Temp controller out Drill not properly Part not clamped Drill not properly sharpened Mode Agitator too slow Pits Temp too high of calibration Hole not drilled sharpened Hole not drilled square in fixture Hole not drilled Effect Extractable too high Internal opens on printed circuit in clean room Conversion rate too low Part will not assemble straight Part will not assemble to proper diameter Lets come up with some Healthcare examples here…
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Linking Failure Modes To Effects Note: The Last Three (3) Examples On Prior Slide
Note that the relationship between the Failure Mode and the Effect is not always 1-to-1.
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A Second Look At The Analysis Section File: FMEA_Form.XLS
Process/Product - FMEA Failure Modes and Effects Analysis Process or Product Prepared by: Page ____ of ____ Name: Responsible: FMEA Date (Orig) ______________ (Rev) _____________ Key S O D R Potential Failure Potential Failure Process Step Process E Potential Causes C Current Controls E P Mode Effects Input V C T N What is the What is the In what ways What is the impact What causes the What are the existing process step Key does the Key on the Key Output Key Input to go controls and procedures FM occur? Process Input go wrong? Variables (Customer wrong? (inspection and test) that cause or FM? to the customer? Sev x Occ x Det Input? Requirements) or prevent either the cause internal How Severe is the effect How often does cause or or the Failure Mode? How well can you detect requirements? Should include an SOP number.
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The FMEA Form The Action Section
Analysis Section R P N Actions Recommended Responsibility Actions Taken S E V O C D E T R P N
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9 Strategies To Complete An FMEA
For each Process Input, determine the ways in which the Process Step can go wrong (Failure Modes) For each Failure Mode associated with the inputs, determine Effects Identify potential Causes of each Failure Mode List the Current Controls for each Cause Assign Severity, Occurrence, and Detection ratings to each Cause Calculate RPN Determine Recommended Actions to reduce High RPNs Take appropriate actions and document Recalculate RPNs SK: Changed the title
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Getting Started Utilize Process Maps, C&E Diagrams, C&E Matrices, data collection, warranty analysis, testing, and other pertinent information Select people from functions both upstream and downstream from the process under analysis Engineering Manufacturing Maintenance Tooling Quality Assurance Marketing Suppliers Health, Safety, and Environment (HSE)
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Exercise # 1: The FMEA Analysis
Provide FMEA Excel files to exercise
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Practical Tips for FMEA
Do not try FMEA alone, it is a group activity FMEA, done right, may be a time consuming process Activities are required for completion, it is not just a paperwork activity The team will likely need training and coaching Prepare properly for meetings Summarize often Make sure voting is independent (suggest anonymous ballots) Negotiate issues SK: Changed the title
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Summary Failure modes and effects analysis (FMEA) is a step-by-step approach for identifying all possible failures in a design, a manufacturing or assembly process, or a product or service. A key output of an FMEA is the “Risk Priority Number.”
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Thank You
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